1. Technical Field
The present invention relates generally to material handling systems, and more particularly to a dunnage bar for use in a dunnage support structure.
2. Discussion
Various articles must be transported in almost every industry. For example, in the automobile industry, parts and components must be shipped from vendors to the automobile manufacturers. Many larger automotive components and subassemblies are shipped in custom designed rack assemblies, or dunnage support structures. These dunnage support structures include a horizontal metal base frame, two vertical end frames, and pairs of vertical support racks located at opposite ends of the horizontal frame. The vertical racks retain dunnage support bars which extend horizontally between a pair of the racks. The dunnage support bars are generally constructed of metal and may have a T-shaped channel for receiving an appropriately formed portion on a dunnage detail or member. The dunnage member slides onto a dunnage support bar and is locked in place longitudinally by dunnage stops which may be bolted or otherwise removably secured to the dunnage bar. The dunnage members are generally plastic or rubber and are formed to uphold and cushion the part or component from potentially damaging impacts while being transported.
The elements of the dunnage support structure are generally of a standard configuration, while the dunnage members are specifically designed for each particular type of part or component transported. The entire dunnage support structure is generally constructed to be disassembled and collapse after the parts have been shipped, in order to return the dunnage support structure to the vendor for use in a subsequent shipment.
Dunnage bars have generally been constructed of extruded aluminum, although steel has also been used. However, aluminum dunnage bars are difficult and costly to manufacture. In view of the fact that aluminum is not only relatively costly, but also readily recyclable, many aluminum dunnage bars are subject to theft. On the other hand, steel dunnage bars are generally heavy and are susceptible to corrosion. The steel bars are also generally not sufficiently flexible, and yield to permanent deformation under relatively light loads.
Accordingly, it is desirable to provide a dunnage bar which is strong, lightweight, abrasion and corrosion resistant, and less susceptible to theft. Furthermore, it is desirable to provide a dunnage bar which is resilient and can accept a wide variety of loads and impacts without permanent deformation. Other factors which affect the design of such a desirable dunnage support bar are size, cost, ease of manufacture, and protection for the articles to be shipped.